Table 1 General characteristics of pregnant and postpartum women according to whether admitted to ICU or not
|  | Pregnancies with ICU admission* (n = 10,204) | Pregnancies without ICU admission* (n = 3,152,099) | Standardized difference†|
|---|---|---|---|
Delivery admissions | 9001 (88.2%) | 3,020,112 (95.8%) | − 0.28 |
Antepartum admissions | 2596 (25.4%) | 250,372 (7.9%) | 0.48 |
Postpartum admissions | 2583 (25.3%) | 58,652 (1.9%) | 0.73 |
Abortions or ectopic pregnancy-related admissions | 918 (9.0%) | 107,097 (3.4%) | 0.23 |
Age (years) (mean ± SD) | 30.5 ± 6.3 | 29.5 ± 5.6 | 0.16 |
 < 15 | 8 (0.08%) | 1191 (0.04%) | 0.22 |
 15–19 | 475 (4.7%) | 136,868 (4.3%) |  |
 20–24 | 1365 (13.5%) | 480,141 (15.3%) |  |
 25–29 | 2491 (24.6%) | 913,371 (29.0%) |  |
 30–34 | 3042 (30.0%) | 1,006,926 (32.0%) |  |
 35–39 | 2026 (20.0%) | 500,255 (15.9%) |  |
 40–44 | 653 (6.4%) | 102,423 (3.2%) |  |
 45+ | 81 (0.8%) | 5932 (0.2%) |  |
Gestational week at delivery admission (weeks) | 36.0 ± 4.7 | 38.7 ± 2.5 | − 0.72 |
Maternal comorbidity index | 1.62 ± 2.06 | 0.47 ± 0.84 | 0.73 |
Live birth | 9005 (88.2%) | 3,020,305 (95.8%) | − 0.28 |
Singleton birth | 8535 (83.6%) | 2,970,321 (94.2%) | − 0.34 |
Twin birth | 484 (4.7%) | 51,029 (1.6%) | 0.18 |
> Triplet birth | 17 (0.2%) | 1780 (0.06%) | 0.03 |
Parity | 0.17 | ||
 0 | 6598 (64.7%) | 1,829,634 (58.0%) |  |
 1 | 1939 (19.0%) | 818,031 (26.0%) | |
 2+ | 1667 (16.3%) | 504,434 (16.0%) | |
Residence rurality (0.7% missing) | - 0.01 | ||
 Urban | 8225 (81.2%) | 2,559,659 (81.8%) |  |
 Rural | 1907 (18.8%) | 568,117 (18.2%) | |
Residence income quintile (14.0% missing) | 0.11 | ||
 Quintile 1 (lowest) | 2603 (29.3%) | 684,917 (25.3%) |  |
 Quintile 2 | 1929 (21.7%) | 571,796 (21.1%) | |
 Quintile 3 | 1659 (18.7%) | 523,475 (19.3%) | |
 Quintile 4 | 1485 (16.7%) | 493,408 (18.2%) | |
 Quintile 5 (highest) | 1212 (13.6%) | 435,658 (16.1%) | |
Hospital rurality (0.6% missing) | − 0.01 | ||
 Urban | 9917 (97.8%) | 3,066,345 (97.9%) |  |
 Rural | 224 (2.2%) | 66,429 (2.1%) | |
Delivery mode | |||
 Vaginal | 2148 (21.0%) | 2,157,286 (68.4%) | − 1.08 |
 Cesarean section | 4425 (43.4%) | 817,172 (25.9%) |  |
Transfer to another institution for acute care | 1594 (15.6%) | 38,350 (1.2%) | 0.54 |
Readmission | 1381 (13.5%) | 42,338 (1.3%) | 0.48 |
Province or territory of admission | |||
 Newfoundland and Labrador | 260 (2.5%) | 51,481 (1.6%) | 0.25 |
 Prince Edward Island | 39 (0.4%) | 15,410 (0.5%) |  |
 Nova Scotia | 226 (2.2%) | 95,713 (3.0%) | |
 New Brunswick | 298 (2.9%) | 80,163 (2.5%) | |
 Ontario | 5967 (58.5%) | 1,524,080 (48.3%) | |
 Manitoba | 376 (3.7%) | 181,367 (5.7%) | |
 Saskatchewan | 494 (4.8%) | 158,537 (5.0%) | |
 Alberta | 1177 (11.5%) | 553,741 (17.6%) | |
 British Columbia | 1308 (12.8%) | 473,437 (15.0%) | |
 Territories | 59 (0.6%) | 18,170 (0.6%) | |
Severe maternal morbidity (any versus none) | 5017 (49.2%) | 44,995 (1.4%) | 1.31 |
 0 (number of severe maternal morbidity events) | 4588 (45.0%) | 3,106,352 (98.5%) | 1.48 |
 1 | 2616 (25.6%) | 41,884 (1.3%) |  |
 2 | 1351 (13.2%) | 2890 (0.09%) | |
 3 | 719 (7.0%) | 625 (0.02%) | |
 ≥ 4 | 930 (9.1%) | 348 (0.01%) | |
Length of hospital stay (days) | 11.1 ± 16.4 | 2.7 ± 3.3 | 0.71 |
Hospital mortality during episode of pregnancy care | 130 (1.3%) | 65 (0.00%) | 0.16 |
Hospital group according to hospital volume of pregnancy | |||
 1 (lowest volume) | 204 (2.0%) | 19,476 (0.6%) | 0.15 |
 2 | 203 (2.0%) | 66,852 (2.1%) | |
 3 | 818 (8.0%) | 211,392 (6.7%) | |
 4 | 2165 (21.2%) | 598,849 (19.0%) |  |
 5 (highest) | 6814 (66.8%) | 2,255,530 (71.6%) | |